Office 365 limits the CIDR you can use on the Connection Filter. If you attempt to add ranges (e.g. 205.139.110.0/23, or 185.58.84.0/22) it won't allow you. To enable you to work around this issue, we recommend breaking up the ranges so they end in /24 instead. To help you with this, we've broken down all IPs from /20 and /22 into /24 for each region below.